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Re: PDF accessibility guidelines. WAS: Re: PDF's and Signatures

From: David Woolley <forums@david-woolley.me.uk>
Date: Mon, 26 Jan 2015 15:48:31 +0000
Message-ID: <54C661CF.7000103@david-woolley.me.uk>
To: w3c-wai-ig@w3.org
On 26/01/15 15:15, accessys@smart.net wrote:
>
> the simple basic fact is that a pdf is a "photo" or "image" of a
> document and no matter what is shown it is still treated or should be
> treated the same as any other image in a document.

PDF's created from machine readable sources are much deeper than 
photographs.  From the typical business users point of view this is 
reflected in the fact that you can print them at arbitrary high 
resolutions.  As I already noted, it is the image like property of 
producing exactly the same layout in every medium that makes them 
attractive (both to people who want to maintain a house style, and to 
people who want to reproduce technical documents without thinking about 
the deep structure).

In W3C terms, PDF is similar to SVG.  Both can embed bit map scans, but 
they are basically both vector plus text formats.  With the right 
authoring tools, text can be very easy to retrieve from PDF, but, in 
practice, word-processors micro-space the text and then encode the 
result as individual, micro-spaced, characters, rather than as a string, 
with associated spacing hints, even though PDF has allowed the latter 
for a very long time.
Received on Monday, 26 January 2015 15:48:37 UTC

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